Internal combustion engine



Feb. 11, 1941. STARR 2,231,173

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INVENTOR ATTORNEY Patented Feb. 11, 1941 INTERNAL COMBUSTION ENGINE Allan M. Starr, Piedmont, Calif., assignor to Starr & Sweetland, San Francisco, Calif., a copartnership composed of Ernest J. Sweetland and Allan M. Starr Original application October 31, 1938, Serial No. 237,925. Divided and this application October 21, 1940, Serial N0. 362,050

5 Claims;

4 This .invention relates to internal combustion engines and has particular reference to the type of engine which receives its fuel in the combustion chamber injected in an atomized state during-the compression stroke, and which utilizes an electric spark for ignition.

The present application is a division of my application Serial No. 237,925 filed October 31, 1938 forlnternal combustion engines, which application describes in detail certain features of engine operation designed to cooperate with the present invention.

An object of my invention is to so arrange the injector and spark gap in a combustion chamber as to facilitate ignition of the injected fuel, and to promote complete combustion of the fuel under various conditions of engine operation.

More specifically, the object of the present illvention is to provide an internal combustion-engine with a combustion chamber into which is directed a multiple orifice fuel injector, and to provide a spark gap in said combustion chamber located between the axes of a plurality of discharge orifices in said fuel injector, so that'ignition commences between the fuel jets and propagates outwardly. Although I do not limit the use and application of the present invention to the specific structure set forth in my application Ser. No. 237,925 above referred to,

I have found that it gives excellent results when used in the manner therein set forth.

The invention possesses other advantageous featuressome of which with the foregoing will be set forth in the following description where that form of the invention which has been selected for illustration in the drawing accompanying and forming a part of the present specification is outlined in full. In said'drawing one form of the invention is shown, but it is to be understood that it is not limited to the specific form illustrated since the inventionis capable of many modifications and is limited only by the scope of the claims attached hereto.

Referring to the drawing:

Figure 1 shows a sectional elevation of a form of cylinder head employing my invention.

Figure 2 shows a diagrammatic elevation on line' 2-4 of Fig. 1 of a four jet fuel spray with spark gap located between the axes of the fuel jets.

Figure 3 is an enlarged sectional elevation showing the lower portion only of one form of fuel injector that may be used advantageously in carrying out the objects of my invention.

Figure 4 is an inverted plan view of the central portion of Fig. 3 showing the multiple orifices of the injector.

Referring to the drawing in detail and particularly to Fig. l, the numeral I designates the combustion chamber wherein the spark gap 2' is formed between the points 3 and 4 which form a part of the spark plug 5. Directed into the combustion chamber is the fuel nozzle 1. This nozzle contains a spring-loaded'valve, normally held closed and is provided with properly proportioned atomizing orifices preferably located near the central axis of the injector. The location of these orifices is designated by the numeral 6.

As fuel nozzles with spring-loaded valves are in general use, it is not deemed necessary to illustrate the details of the nozzle valve in the present instance. The combustion, chamber I may be of the form illustrated in Fig. 1 but I do not limit myself to this particular form of combustion chamber as various modifications of this form, and other'forms of combustion chamber, may be used advantageously in connection with 7 l1 represents the inlet valve which is guided.

by the bushing I8 and is seated by spring IS; the inlet air entering through passage 2| which connects with the air. inlet manifold (not shown). The engine piston is shown at the top of its stroke. Fuel is fed to the'nozzle I and out through the apertures 6 through the conduit 8 which connects with the fuel pump (not shown). In the opera-tion of the engine herein illustrated and described it is assumed that a suitable fuel pump, orfuel injecting device of any desirable make is used to feed the fuel through the conduit 8. An alternate method of carrying out my invention is to force the fuel out of the aperture t by individual metering plungers located in each injector nozzle and operated by a cam shaft extending along the cylinder head.-

Either of these metering systems will produce satisfactory results but since they form no part of the present invention, they are not described in detail. It is assumed that whatever method of injection is used, the'fuel' is forcibly projected .through the nozzle apertures to a depth at least approximately opposite the spark gap 2, preferably during the compression stroke, and in proper timing with the engine cycle.

Referring to Fig. 2, numerals 3 and 4 represent the spark points projecting into the combustion chamber, and the lines 3m and 32a represent two fuel jets straddling the spark gap.

In Fig. 3 which shows only the lower end portion of the nozzle in sectional elevation, numeral 33 represents the valve seat plate, which is provided with central passage 34 through which fuel is supplied to the nozzle orifices 6. 35 is the spring-loaded plunger, the lower portion of which is reduced in diameter to form the shoulder 36'and the valve 31, while the lower face is ground perfectly flat to seat against the flat ground upper face of the valve seat plate 33. 38 is a cavity in the block 39 into which fuel is fed through the duct 4| which is in direct communication with the conduit 8. When a charge of fuel under pressure enters cavity 38 through the duct 4|, pressure exerted under the shoulder 36 lifts plunger 35 to discharge the fuel forcibly throughthe divergent orifices 6, and when the fuel pressure subsides in cavity 38 the spring (not shown) which loads plunger 35 rapidly returns the plunger to the closed position illustrated.

In Figure 4 the openings of the nozzles 5 are clearly shown. For purposes of illustration I have shown four nozzle openings but any number from two upward may be employed in carrying out the objects of my invention.

The spark points 3 and 4 extend out into the combustion chamber as shown in Figure 1. When I use a combustion chamber of the form shown in Fig. 1, I prefer to locate the points 3 and 4 so that the spark gap 2 is located substantially upon the central axis of the combustion chamber, and to have the central axis of the fuel injector in line with the axis of the combustion chamber.

When this arrangement is followed the axes of the fuel jets 3i and 32 are substantially equidistant from the spark gap and within the zone penetrated by said jets, whereby ignition starts at the central axis and propagates outwardly. The fuel jets and the spark wires are preferably positioned so that no fuel jet impinges directly on either spark wire. If a two orifice nozzle is used the nozzle is. positioned so that one jet is projected on each side of the spark gap. If a four jet nozzle is used then the nozzle is positioned so that two jets project on either side of the spark wires so that the fuel spray does not impinge upon the wires. When five or more jets are used the spark plug wires extend into the chamber between two of the jets.- The spark plug 5 is preferably located so that the grounded wire 4 is beneath the insulated wire 3-and any suitable means may be used to produce a spark between the points 3 and 4. The ordinary spark coil or magneto are examples of the simplest means of producing a satisfactory spark and the spark plug 5 is wired to the magneto or coil and battery in accordance with usual practice, it being assumed that suitable means of timing the injection and ignition to obtain the maximum efllciency of the engine are provided.

In the drawing Fig. 1 it is assumed that a four jet nozzle is employed and the lines 3| and 32 represent the axes of the jets from the two orifices located on the far side of the nozzle as showninthis view.

The size of the nozzle openings and the angle included between the axes thereof are correlated with the size and shape of the combustion chamber. As shown in Figures 1 and 2 the ignition spark gap is located substantially midw y piston moves upwardly the contents of the cylto the best advantage regardless of the load and speed of the engine.

. In the operation of my engine the inlet valve I! is-open during the downward stroke while air is being drawn into the cylinder through the port 2!. The inlet valve I1 closes as the piston starts upward on its compression stroke. As the inder and combustion chamber are compressed. Preferably toward the end of the compression stroke fuel is injected from the orifices 6 through the hot residual gases compressed in the combustion chamber. The spark occurs at the gap 2 which is in contact with the fringes of the jets where ignition takes place and the flame rapidly spreads outwardly, igniting the entire fuel charge.

It should be understood that ignition takes place more readily and satisfactorily at the fringes of the jets than when the spark is in the direct path of a jet of fuel being forcibly projected into the combustion chamber. The fuel being ignited, the piston is forced downwardly and the operation continues in the customary manner of the four cycle engine.

By the arrangement shown, of locating the spark gap between the axes of the jets, ignition takes place to the best advantage whether the engine is idling or running at light load, or whether it is heavily loaded or running at high speed. For instance, if the engine is idling then the fuel charge projected from the nozzle apertures is very light and does not project much beyond the spark points. In this instance, ignition takes place on the fringe near the end of each projected jet. When the engine is speeded up or is given a heavy load, the jets project forcibly past the spark points, .but since the spark points are not impinged upon directly, but .are straddled by the jets, the spark still'is located in the most advantageous position to'start ignition at the center and the flame propagates evenly and outwardly as explained.

The arrangement of injector nozzle and spark points herein described is particularly applicable to my invention above referred to, which is set forth in application Serial No. 237,925, because this arrangement does not disturb the desired quiescence in the zone of the combustion chamber most remote from the cylinder, nor does it interfere with turbulence in the combustion chamber which it is desired to have take place during the last few degrees of crank angle of the compression stroke.

In the drawing I have illustrated a simple form of nozzle with divergent orifices. It is within the province of my invention to vary the design of nozzle and the position of the orifices, so long as thenozzle is arranged and constructed to produce divergent jets for the reasons herein set forth.

I claim:

1. An internal combustion engine comprising a cylinder and a cylinder head; an elongated combustion chamber in said cylinder head; an injector nozzle in the end of said combustion chamber most remote from said cylinder; a spark plug having a spark gap in said combustion chamber; said injector nozzle having a plurality 75 of diverging fuel discharge apertures; said spark gap being located between the jets projected by said apertures and being positioned within the zone penetrated by said jets, whereby,ignition and flame propagation is started between the jets projected by said apertures.

2. An internal combustion engine comprising a cylinder and a cylinder head; a combustion chamber in said'cylinder head; an injector nozzle in said combustion chamber; a plurality of fuel apertures in said injector nozzle, said apertures diverging relative to the longitudinal axis of said injector'nozzle; and a spark gap in said combustion chamber located substantially in line with the central axis of said injector nozzle at apoint within the depth penetrated by jets projected from said apertures. v

3.4 An internal combustion engine comprising a cylinder and a cylinder head; a combustion chamber in said .cylinder head; an injector noz- -zle in said combustion chamber; a plurality oi which said spark gap is formed being located between and within the range of the sprays projected by certain of said apertures to avoid direct impingement oi the spray from said apertures upon said conducting elements.

4. An internal combustion engine comprising, a cylinder; a cylinder head secured to said cylinder, said cylinder head having a combustion chamber; an injector nozzle in said combustion chamber, said injector nozzle having a plurality of fuel apertures, said apertures diverging relative to the longitudinal axis said injector nozzle; and a spark gap in said combustion chamber located substantially in line with the central axis of said injector nozzle and within the zone of penetration of fuel jets projected from said aperturs, said spark gap comprising an insulated wire and a grounded wire. the grounded wire being located beneath said insulated wire.

5. An internal combustion engine comprising a cylinder and a cylinder head; a combustion chamber in said cylinder head; an injector nozzle in the end of said combustion chamber most remote from said cylinder; a spark plug having aspark gap in said combustion chamber; said injector nozzle being arranged and constructed to project a plurality of diverging fuel jets into said combustion chamber; said spark gap being located between said jets and within the zone of penetration of said jets whereby ignition and flame propagation is started between the jets projected in said combustion chamber.

ALLAN M. STARR. 

